Caster



Feb. 22, 1966 A. E. RICE ETAL 3,235,901

CASTER Filed Oct. 2, 1962 INVENTORS ALBERT E.RICE FORD A. RICE ATTORNEYS United States Patent Ofiice 3,235,901 Patented Feb. 22, 1966 3,235,901 CASTER Albert E. Rice and Ford A. Rice, Cleveland, Ohio (both of PD. Box 277, Warren, Pa. 16365) Filed Oct. 2, 1962, Ser. No. 227,837 2 Claims. (Cl. 16-18) This invention relates generally to casters, but has reference more particularly to improvements in the caster disclosed in our copending application, Serial No. 82,943, filed January 16, 1961, and allowed June 18, 1962, now Patent No. 3,075,232.

In the caster of the aforesaid copending application, the herni-spherical floor-engaging element of the caster has its axis in alignment with the axis of the other or coacting or supporting hemi-spherical element of the easter. As a result, the first-named hemi-spherical element, which has the spherical inclined segmental protuberance which provides the tread which engages the floor in the use of the caster, has acenter of gravity which is relatively high in relation to the axis of the other or coacting hemi-spherical. element, and we have found that this inhibits the rolling action of the tread-bearing element to some extent.

Moreover, the aforesaid arrangement of the two elements is such that the spherical inclined segmental protuberance or tread forms a pocket with the stem and associated parts of the caster, which pocket provides a receptacle or space in which lint and other foreign matter accumulates, thereby further interfering with the rolling action of the caster.

We have found that by offsetting the axis of the treadbearing element of the caster downwardly in relation to the axis of the other element, not only is the center of gravity of the tread-bearing element lowered, in a manner to improve the rolling action or rollability of the treadbearing element, but the pocket, to which reference has been made above is eliminated, thereby further improving the rolling action.

Other objects and advantages of our invention will be apparent during the course of the following description.

In the accompanying drawings forming a part of this specification, and in which like numerals are employed to designate like parts throughout the same.

FIG. 1 is a front elevational view of a caster embodying the invention;

FIG. 2 is a side elevational view of the caster, as viewed from the right side of FIG. 1;

FIG. 3 is a fragmentary cross-sectional view, taken on the line 3-3 of FIG. 2;

FIG. 4 is an exploded view of the caster, with portions of the parts broken away to more clearly show the construction of the parts;

FIG. 5 is a top plan view of the caster, and

FIG. 6 is an elevational view of the caster-supporting element.

Referring more particularly to the drawings, the caster is seen to comprise a rotary floor-engaging element 1, of substantially hemi-spherical form, and a body or supporting element 2, also of hemi-spherical form, the elements 1 and 2, when joined in the manner described in our aforesaid pending application, forming substantially a sphere or ball.

The element 1 is provided with a spherical segmental protuberance 3, which is inclined to the vertical axis of the sphere and forms a tread which engages the floor at all times during use of the caster, the protuberance 3 having end surfaces 4 and 5 which lie in flat parallel planes.

The element 1 is provided with a central hub 6 which extends axially along the axis AA of the element 1 and in a direction substantially perpendicularly to the planes of the end surfaces 4 and 5, and to a point beyond the plane of end surface 5.

The hub 6 is surrounded by an annular recess 7, for a purpose to be presently described, and the hub has an axial bore 8 therein, which bore has a rounded bottom 9, the wall of the bore having an annular groove 10 therein intermediate the ends of the bore. The axis AA of the bore is inclined to the vertical axis of the caster.

The element 2 is provided with a portion 11, which, as best shown in FIGS. 2 and 6, extends upwardly and tangentially to the element 2 and is formed, cast, or molded integrally therewith, this portion 11 having a bore 12 therein, which has a rounded bottom 13, and an annular recess or groove 14 in its side wall.

The element 2 is also provided with an inclined fiat face 15 which is substantially parallel with the end surface 5 of the element 1 and is disposed closely adjacent said end surface. The element 2 is further provided with an annular flange 16 which extends from the face 15, which forms a thread guard, and which, when the elements 1 and 2 are assembled, extends into the recess 7 of the element 1, as best shown in FIG. 3.

The element 2 has a recess 17 of a diameter not substantially in excess of the external diameter of the end of the hub 6, and of relatively shallow depth and having a bottom 18 disposed in a plane parallel with the face 15, said recess adapted to receive the end of the hub 6, when the elements 1 and 2 are assembled with each other.

The element 2 is further provided with an axle or shaft 19, which may be made of steel or similar material, and which is preferably cast into the element 2 when the latter is molded or cast, whereby the axle is rigidly secured to the element 2 and is non-rotatable within the element 2.

It is to be noted, at this point, that the axle or shaft 19 is so mounted in the element 2 that its axis is in alignment with the axis A-A of the element 1, but is spaced somewhat below and parallel with the axis BB of the element 2. As a result, when the element 1 is assembled with the element 2, as best seen in FIG. 3, the axis AA of the element 1 is offset downwardly in relation to the axis BB of the element 2, thereby lowering the center of gravity of the element 1 in a manner which improves the rolling action or rollability of the element 1. At the same time, the spherical segmental protuberance 3 of the element 1 is lowered sufiiciently, as best seen in FIG. 3, to eliminate formation of a pocket, at the point C, thereby eliminating an area or space within which lint and other foreign matter can accumulate to interfere with the rolling action of the element 1.

The axle or shaft 19 extends from the element 2 in a direction perpendicularly to the flat face 15, and has a rounded end 20, which is adapted to bear against the rounded bottom 9 of the bore 8, so that the bottom 9 provides, in effect, an end thrust bearing for the axle 19.

The axle 19 is provided adjacent its lower end with an annular recess or groove 21, in which a split ring 22 is disposed, for a purpose to be presently described.

The axis of the bore 12, it may be noted, is not only olfset horizontally from the axis of the shaft 19, but is also inclined to the latter, as is customary in this type of caster.

The caster further includes a stem 23, preferably of steel, which is adapted to be attached to an article of furniture or the like, and is provided with a rounded lower end 24, which is adapted to bear against the rounded bottom 13 of the bore 12, so that the bottom 13 provides, in effect, an end thrust bearing for the stem 23.

The stem 23 is provided with an annular recess or groove 25, in which a split ring 26 is disposed, for a pur pose to be presently described.

In the assembly of the elements 1 and 2, the axle or shaft 19 is inserted into the bore 8 of the element 1, and during this assembly, the split ring 22 is contracted slightly by the wall of the bore 3, and then expands to enter the groove or recess 10, when the parts are in the rela tive position shown in FIG. 3, thereby locking the elements 1 and 2 against axial displacement from each other. The split ring 22 fits loosely in the recess 10, so as not to interfere with the free rotation of the element 1.

In the assembly of the stem 23 with the element 2, the stem is inserted into the bore 12 of the element 2, and during this assembly, the split ring 26 is contracted slightly by the wall of the bore 12, and then expands to enter the groove or recess 14, when the parts are in the relative position shown in FIG. 4, thereby locking the stern and element 2 against displacement from each other. The split ring 26 fits loosely in the recess 14, so as not to interfere with the free rotation of the element 2 about the stem 23.

The elements 1 and 2 may be made of plastic, or in the form of metal die castings or forgings, and in order to facilitate rigid securement of the axle 19 to the element 2, when the axle is cast into the element 2, the exterior surface of the axle 19 may be knurled or otherwise roughened.

If desired, the axle or shaft 19 may be made as a separate part which can be removably secured to the element 2, as by threading it into a threaded bore of the element 2, or it may be inserted into the bore and peened to the element 2, so as to be locked against displacement from the latter.

For the purpose of lightening the elements 1 and 2, the element 1 may be provided with a series of circumferentially-spaced holes 27, and the element 2 may likewise be provided with a series of circumferentially-spaced holes 28.

It is to be understood that the form of our invention, herewith shown and described, is to betaken as a preferred example of the same, and that various changes may be made in the shape, size and arrangement of parts thereof, without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described our invention, we claim: 1. In a caster as described having a first portion and a second portion assembled together and having substantially spherical outer surfaces, said first portion being a tread bearing floor engaging element with a protuberance and having a central hub having a bore therein, said protuberance being disposed eccentrically to the spherical axis of said second named portion, said second named portion having a spherical axis which is inclined and having an inclined flat face which lies in a plane normal to said spherical axis and is substantially parallel with the planes of the end surfaces of the protuberance of said first-named portion and is disposed closely adjacent one of said planes, said second named portion having an axle secured therein and extending into said bore, the axis of said axle being spaced downwardly from and being parallel with said spherical axis of said second named portion, whereby the center of gravity of the first named portion is lowered in a manner to lower the tread and improves the rolling action of the first named portion.

2. In a caster having a first portion and a second portion assembled together and having substantially spherical outer surfaces, the first portion being a rotatable tread bearing element inclined at an acute angle to the vertical and concentric to an inclined axis of the second portion, said axis of the second portion being disposed downwardly from the normal axis of the second named portion so that the tread surfaces of the first named portion is level with the top surface of the second portion and extended below the bottom portion of the second named element to improve the rolling action of the caster.

References Cited by the Examiner UNITED STATES PATENTS 2,082,798 6/1937 Herold 1618 2,539,108 1/1951 Shepherd 16-18 FOREIGN PATENTS 272,796 4/1951 Switzerland.

JOSEPH D. SEERS, Primary Examiner.

DONLEY I. STOCKING, Examiner. 

2. IN A CASTER HAVING A FIRST PORTION AND A SECOND PORTION ASSEMBLED TOGETHER AND HAVING SUBSTANTIALLY SPHERICAL OUTER SURFACES, THE FIRST PORTION BEING A ROTATABLE TREAD BEARING ELEMENT INCLINED AT AN ACUTE ANGLE TO THE VERTICAL AND CONCENTRIC TO AN INCLINED AXIS OF THE SECOND PORTION, SAID AXIS OF THE SECOND PORTION BEING DISPOSED DOWNWARDLY FROM THE NORMAL AXIS OF THE SECOND NAMED PORTION SO THAT THE TREADS SURFACES OF THE FIRST NAMED PORTION IS LEVEL WITH THE TOP SURFACE OF THE SECOND PORTION AND EXTENDED BELOW THE BOTTOM PORTION OF THE SECOND NAMED ELEMENT TO IMPROVE THE ROLLING ACTION OF THE CASTER. 